I bought an Auto Gear M-23Z off a board member that decided to go TKX. An M-23Z is a Muncie clone with everything better than Muncie designed. It is an utra-wide ratio transmission with a 2.98:1 first gear and an even drop between each gear with a 1:1 4th gear. I have had it for almost 3 years now and I finally, FINALLY got to install it in my GS 350 with the freshly rebuilt 350. To say I was excited would be an understatement. It looks like a beefy Muncie if no cost were spared. It bolts to the bellhousing, the same clutch splines and and the shifter bolted up like factory, complete with back drive for the reverse to lock the column. The only issues I had were minor. First, I had the drive shaft shortened, a new yoke put on because even the Muncie felt like at full droop, it was too tight. Second, the back drive stud had to be reworked due to the change in thread size on the two transmissions. So, after finally getting everything together, we took it for the first test drive. Now, if you have 3.08 rear gears and an M21, you know it feels like taking off in second gear. It feels painful to me. When compared to the M-21 2.20:1 first gear, the 2.98:1 M-23Z first gear makes the 3.08:1 rear gears take off like it has 4.11:1 rear gears. My wife can drive it and didn't kill it. Compared to the M-21 and the M-20 I'd had in it before, it was very firm in shifts. It takes a little more effort to get the shifter to move into gear but not excessive. It also whines a bit in the lower gears like an M-22 would but it largely goes away in 4th gear. Overall, if you have a Muncie but want something different, the M-23Z is a pretty sweet option that most people wouldn't notice if they looked under it.